The sport of archery includes activities ranging from target practice to game hunting, and the art of providing arrows suitable for each of such purposes has become highly developed. A great many types of arrowheads have been developed, with each designed to serve a particular purpose and having specific operating characteristics. Thus, arrowheads specifically intended for hunting large, thick-skinned, heavy-boned game such as bear have been developed as well as heads particularly suitable for hunting large thinner-skinned, lighter-boned game such as deer. Arrowheads have also been developed for hunting fowl, particularly turkey, for hunting squirrels and other small game, and for bow-fishing. When such specially designed arrowheads are attached to the arrow shaft in non-releasable fashion, it is necessary for the archer to have a wide range of arrows, some for target shooting, some for hunting larger game, some for smaller game. Prior-art workers therefore proposed arrows having interchangeable heads, in an effort to reduce the number of arrow shafts which might be required, as in U.S. Pat. Nos. 2,289,284 Chandler and 3,910,579 Sprandel, but such approaches require replacement of the entire arrowhead and therefore have the drawback that a complete new arrowhead must be manufactured for each intended use.
Arrowheads with interchangeable blades have been proposed by prior-art workers in an effort to increase the versatility of the arrowhead while economizing in the amount of materials needed for production. Systems typical of this general approach are disclosed in U.S. Pat. Nos. 2,940,758 Richter, 4,036,479 Sherwin, 4,146,226 Sorenson and 4,210,330 Kosbab. Such systems typically employ a plurality of independent blades each of which can be fitted into a different one of a plurality of slots in a central body. Usually, the blades are then clamped by axially-acting clamp members which are separate from the arrowhead body, or the body itself may act as a clamp member. Such systems are cumbersome to assemble because each blade must be handled individually. Further, since a plurality of blades are clamped, the blades tend to be held less securely and tend to become loose during use. Since the blades themselves must be clamped to the arrowhead body, there is an increased liklihood that the blades will fracture or shear on impact, at or near the points where the blade is clamped.
U.S. Pat. Nos. 3,741,542 Karbo and 4,349,202 Scott illustrate prior-art arrowheads in which blade assemblies comprising two or more blades are releasably secured to the arrowhead body. Though such arrowheads represent a distinct improvement in the art, they have the deficiency that, when the blades are of substantial size, the clamping forces are applied to only a limited portion of the blade, so that the blade is likely to fracture or distort under the rigors of use. In other approaches, as in U.S. Pat. No. 3,398,960 Carroll, a blade structure is positioned over a central shaft and locked thereto, but such approaches have the deficiency that the entire blade structure is external and more easily deformed or loosened on impact. While prior-art proposals have achieved significant acceptance in the trade, there has been a continuing need for improvement, particularly in the ease of assembly of the arrowhead and its ability, once assembled, to withstand the rigors of actual use.